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Modeling the effect of time-dependent exposure on intensive care unit mortality

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Abstract

Purpose

To illustrate modern survival models with focus on the temporal dynamics of intensive care data. A typical situation is given in which time-dependent exposures and competing events are present.

Methods

We briefly review the following established statistical methods: logistic regression, regression models for event-specific hazards and the subdistribution hazard. These approaches are compared by showing advantages as well as disadvantages. All methods are applied to real data from a study of day-by-day ICU surveillance.

Results

Standard logistic regression ignores the time-dependent nature of the data and is only a crude approach. Cumulative hazards and probability plots add important information and provide a deep insight into the temporal dynamics.

Conclusion

This paper might help to encourage researchers working in hospital epidemiology to apply adequate statistical models to complex medical questions.

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Abbreviations

NP:

Nosocomial pneumonia

ICU:

Intensive care unit

PAF:

Population attributable fraction

OR:

Odds ratio

HR:

Hazard ratio

CI:

Confidence interval

PHREG:

Proportional hazards regression

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Acknowledgments

We thank the four anonymous reviewers for their comments and Caroline Mavergames for checking the final manuscript for English language grammar and style. They helped to improve the manuscript. This project was funded by the Deutsche Forschungsgemeinschaft DFG, project FOR 534.

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Authors and Affiliations

  1. Institute of Medical Biometry and Medical Informatics, University Medical Center Freiburg, Stefan-Meier-Straße 26, 79104, Freiburg, Germany

    Martin Wolkewitz, Jan Beyersmann & Martin Schumacher

  2. Freiburg Centre for Data Analysis and Modelling, University of Freiburg, Eckerstraße 1, 79104, Freiburg, Germany

    Martin Wolkewitz & Jan Beyersmann

  3. Institute of Hygiene and Environmental Medicine, Charité-University Medicine Berlin, Heubnerweg 6, 14059, Berlin, Germany

    Petra Gastmeier

Authors
  1. Martin Wolkewitz
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  2. Jan Beyersmann
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  3. Petra Gastmeier
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  4. Martin Schumacher
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Corresponding author

Correspondence to Martin Wolkewitz.

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Wolkewitz, M., Beyersmann, J., Gastmeier, P. et al. Modeling the effect of time-dependent exposure on intensive care unit mortality. Intensive Care Med 35, 826–832 (2009). https://doi.org/10.1007/s00134-009-1423-6

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  • DOI: https://doi.org/10.1007/s00134-009-1423-6

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